Braking arrangement comprising an hydraulic decelerator



E. ROHACS Match 19, 1968 BRAKING ARRANGEMENT COMPRISING AN HYDRAULICDECELERATOR Filed Feb. 23, 19466 N .um

United States Patent I O 8,443 7 Claims. (ci. iss- 90) ABSTRACT F THEDISCLUSURE A braking hydraulic decelerator in which the decelerator issimultaneously supplied directly from the cooling system of the vehicleand directly from an auxiliary supply reservoir.

The invention relates to a new method of using hydraulic decelerators.

It is known that hydraulic decelerators cannot suffice to ensure thebraking of automobile vehicles in the sense in which the word braking isgenerally used, and denotes the possibility of stopping the vehicle ifnot instantaneously, at least in a minimum of time acceptable for agiven speed. Also hydraulic arrangements are considered as capable onlyof ensuring a limited deceleration before being completed by the use ofa mechanical brake, if it is desired to come to a stop-or capable ofpreventing accelerations. Whence comes their name of decelerators.

The inadequacy of decelerators in the conditions demanded practicallyfor an arrangement capable of being regarded as a brake has, for one ofits principal causes, the time necessary for lilling up the deceleratorwhich, when proceeding normally, should be empty of liquid in order notto absorb the shaft power unnecessarily.

The arrangements comprising an hydraulic decelerator, the heat exchangerof which is formed by the radiator of the vehicle, includes lengths ofpipe relatively long with as small a diameter that it is possible, inpractice, to give to them.

The arrangements with an independent heat exchanger are more costly,they offer the advantage of not bringing about a lowering of the levelin the radiator of the engine of the vehicle during the functioning ofthe decelerator, but it is often diicult to `accommodate such exchangersin the immediate vicinity of the decelerator and from the point of viewof the time of the lling they cannot offer a considerable advantage and,in any case, one sufricient to be able to attain the desirable order ofmagnitude.

A lower filling time can be obtained with arrangements with anindependent heat exchanger, the liquid charge of which is normallycontained in a cylinder from which it is driven by means of compressedair in order to iill the decelerator, but the arrangements used havesomewhat slow response times, and as the present inventor hasrecognized, can be, in themselves, the object of considerableimprovement on this point.

A first object of the invention is to preserve the advantages which theradiator of the vehicle offers as a heat exchanger.

These advantages include a greater volume of liquid in circulation andgreater surface of radiation.

While avoiding the major disadvantages of one part of this radiatorincludes a lowering of the level and its remoteness, it also alleviatesthe disadvantages of an independent heat exchanger.

With these objects in view concomitant use is made of the said radiatorand of a filling cylinder, and this without making use ofan independentheat exchanger.

A second object of the invention is to reduce the time of lilling of thedecelerator and correlatively the empty* ing time.

With this object in view the invention makes use of simultaneousfilling, starting from the filling cylinder and starting from the massof water circulating in the general cooling system of the engine of thevehicle-more particularly and additionally, supplying the deceleratorstarting from the jacket of the engine cylinders in such a way as toreduce the length of the piping and to take advantage, of the excesspressure at this point created by the circulating pump, if any.

The third object of the invention is to obtain a supplementaryimprovement for a given time of functioning, by augmenting the speed ofevacuation and of return of the liquid.

With this object in view the invention provides for the replacement ofthe classic cylinder by an extremely flat diaphragm receiver, a receiverthe form of which is designed in order that the emptying may be total,that is to say, the form of which approaches as nearly as possible theform which the diaphragm tends to take when it is subjected to theaction of compressed air.

Having thus, by means of the two means indicated above, improved in aconsiderable way the time of illing of the decelerator, it is recognizedthat it is possible to use the decelerator not only in a way that is tosome extent incidental and subjective, the driver operating thedecelerator by an independent control every time that he thinks itnecessary to do so, but by using systematically the hydraulicdeceleration as the irst phase of any braking operation, the secondphase of which is then mechanical. Hence, one alleviates thedisadvantage which 4hydraulic ydecelerators have shown hitherto incomparison with electric decelerators.

With this object in view the invention divides into two parts the courseof the control member of the mechanical brake, that is to say, inpractice the course of the usual brake pedal. The first part of thecourse brings about the progressive actuation of the decelerator, thesecond part the progressive actuation of the mechanical brake,understanding by the mechanical brake, a brake of which the frictionmember is mechanical; even if the transmission is hydraulic orpneumatic.

The arrangement according to the invention thus makes possible the-avoidance of the use and therefore of the Wear of the lining of themechanical brakes whenever it is only a matter of obtaining a temporarydeceleration without coming to a stop, which is at present the case inthe majority of the braking occurrences for buses or lorries of urbanservice, the presence of a source of compressed air on which is alreadyin general use.

As will be shown hereafter this improvement does not exclude thepossibility of putting the decelerator into a state of permanentoperation, for example in the course of a long descent.

' Although intended for use by buses and lorries the invention will alsofind application in other iields, for example that of the engines ofhoisting machines, in particular those which comprise an internalcombustion engine and more particularly still those in which the engineis controlled by compressed air as is often the In FIGURE 1 is shown bymeans of 1 the hydraulic decelerator in its entirety-a decelerator ofwhich a great number of types exist which have been either proposed orcarried out, for example, that which was described in English Patent842,145 due to the present inventor.

The supply of the decelerator is taken at 2 from the jacket of theengine 3.

The decelerator discharges during its functioning into the radiator 4 ofthe vehicle by means of the output pipe 5 while 6 is the dischargepiping.

On the supply piping 7 is the usual valve 8 which is normally controlledin the actual installation by a manual control and which, according tothe present invention, is controlled by the brake pedal 9 by means ofthe cornpressed air servomotor 29.

In the immediate vicinity of the decelerator 1 is the filling reservoir10y a detailed description of which will be given later.

This filling reservoir communicates by a large diameter piping 11 withthe decelerator, this piping being connected to the said decelerator bya T-tube 12 on the other branch of which is branched the dischargepiping 6.

The piping 13 is the compressed air piping starting Vfrom the reservoirof the vehicle-a reservoir which has not been shown.

The piping 13 arrives at the distributor valve 14 which permits ofconnecting the piping 13 with the piping 15 which itself is connected tothe reservoir 10. In a second position the distributor valve 14 closesthe supply of compressed air by the piping 13 and connects the piping 15to the atmosphere via the purge 16.

As may be seen in the figure, the compressed air servomotor is simply asmall piston jack, the compressed air acting on one face of the pistonagainst the action of the spring which bears on the opposite face of thepiston.

Although this has not been shown in the drawing it will be easilyunderstood that it is possible to establish a by-pass piping whichpermits of short-circuiting the valve S, this by-pass tubing in its turncomprising a bypass valve which may be controlled manually by a remotecontrol starting from the cabin of the vehicle.

Turning now to FIGURE 2, it is seen that the reservoir 11i is formed inthe following way:

It shows in the rst place an extremely fiat form composed of a base 17which, seen from outside, presents a very slightly convex form and adished part 18, the two parts 17 and 18 gripping by means of flanges adiaphragm 19 the general form of which is circular.

The gripping of the diaphragm between the two flanges is hererepresented as carried out by a series of bolts such as 20, but ofcourse one can use for this gripping the various means which are alreadyknown for diaphragm devices of this kind.

At 21 is shown, by broken lines, the position of the diaphragm when itis partially stretched by the action of compressed air which arrivesthrough the pipe 15.

It will be easily understood that if the diaphragm continues to stretchit will come to be closely applied over the whole of the dished part 18.

The upper compartment of the reservoir designated by 22 is joined to thepiping 11, itself connected to the decelerator 1, by a coupling head 23formed by a valve, subjected to a spring and normally open, in such away that the diaphragm covers the head of the obturator 24 at thealignment of the wall of the part 18 in order to avoid having thediaphragm penetrating the interior of the coupling head due to pressurein the lower compartment 25.

The pedal 9 controls the distributor valve 14 by means of a linkage, ofwhich a telescopic link 26 forms part, which allows, when thedistributor lever is at the end of its travel, the pedal to continue itsmovement against the action of the spring 27 and to actuate the usualbraking arrangement (not shown).

The device operates as follows:

The pedal being in its rest position, the distributor keeps the supplyof compressed air shut off while the purge is open.

The servomotor 29 is then in the position shown and keeps the valve 8shut.

The diaphragm of the reservoir 10 is relaxed and applied to the bottomof the reservoir under the weight of the water which iills it.

By compressing the pedal over a part of its total movement thedistributor closes the purge and opens the supply of compressed air,operating on the one hand on the servomotor 2.9, which instantaneouslyopens the valve 8, on the other hand on the diaphragm of the reservoirwhich stretches, driving out the water contained in the compartment 22in part into the decelerator and in part into the radiator by means ofthe discharge tube 6.

The water thus passes from two sides into the decelerator and this canconsequently have immediate effect.

To actuate the normal brake the driver continues to depress the pedal inaccordance with the desired eiect without modifying the action of thedecelerator, from the moment at which the distributor valve 14 hasarrived at the end of its travel.

The telescopic link 26 allows of the pedal being pressed to the bottomwithout notable additional resistance.

By releasing the pedal progressively the action of the normal brakes isreduced or even stopped and by releasing the pedal completely thedecelerator in its turn ceases to act, because, the distributorreturning to its purge position the servomotor 29, by the action of itsreturn spring, closes the valve 8, thus the supply of water to thedecelerator ceases and the water in the decelerator is expelled into thereservoir on the one hand by gravity, on the other hand by the suctioneffects of the diaphragm, the latter seeking to relax.

The air compartment 25 being likewise in communication with theatmosphere offers practically no resistance to the return of thediaphragm to its relaxed position.

What I claim is:

1. A braking arrangement comprising an hydraulic decelerator, the heatexchanger of which is constituted by the radiator of the vehicle, inwhich the decelerator is supplied simultaneously from the cooling systemof the Vehicle and from an auxiliary supply reservoir, said auxiliarysupply reservoir being divided into two compartments by a diaphragm andincluding means for introducing fluid under pressure into the irstcompartment, the second compartment being connected to said decelerator.

2. An arrangement as claimed in claim 1 in which the form of thereservoir is such that one part of the diaphragm applies itself to aflat bottom when the second compartment is full of liquid and appliesitself to the whole of the surface of a concave wall when the firstcompartment is full of fluid under pressure.

3. A braking arrangement for a vehicle having a motor and a coolingsystem containing coolant liquid vfor said motor, said cooling systemincluding a heat exchanger comprising:

(a) said cooling system containing said coolant liquid,

(b) a decelerator,

(c) means for connecting said decelerator to said cooling system,

(d) an auxiliary supply reservoir,

(e) second means for directly connecting said reservoir and saiddecelerator,

(f) said decelerator being supplied simultaneously with said coolantliquid from said cooling system and from said reservoir and said coolantliquid being discharged simultaneously from said decelerator to saidreservoir and to said cooling system.

4. A braking arrangement as claimed in claim 3, in

which the supply of the decelerator takes place by two 5 distinctentrances, the rst connected respectively to the said circuit and thesecond to the said auxiliary reservoir.

5. An arrangement as claimed in claim 4 in which the said first entranceis connected to the jacket of the engine of the vehicle.

6. An arrangement as claimed in claim 4 in which a first valve controlsthe said first entrance into the decelerator and a second valve controlsthe entrance of the fluid under pressure into the reservoir and means ofcontrol are provided for simultaneous opening of the two valves.

7. An arrangement as claimed in claim `6 in which the said means ofcontrol are actuated by the usual brake pedal only in a rst part of thebraking travel of the 6 actuated by the said pedal only during a secondpart of the said travel whereby said means of control and said usualmeans of braking are simultaneously actuated in said second part of saidtravel.

References Cited UNITED STATES PATENTS 2,766,589 10/1956 -OLeary 60-543,051,273 8/1962 Cordiano et al 60--54 X 3,057,666 10/1962 Sieving etal. 18S-90 X 3,124,218 3/ 1964 Montgomery 18890 MILTON BUCHLER, PrimaryExaminer.

pedal while the usual means of braking the vehicle are 15 G E HALVOSA,ASSSmm Examiner-

